This invention relates to headsets, particularly headset used to give commands to a microcontroller based device.
In the embodiments disclosed in the application, gaining random access to various functions using the momentary (normally-closed) headset switch involves pushing the button in various patterns (click, double-click, hold, etc.). The off-hook detector detects the two states of the push button switch by sensing the DC voltage to ground of the line that is broken by the push button switch.
Since there are two headset interconnect wires (along with a third, common ground return), it is possible to have two such switches: one for each wire. The switches would be independent system inputs, having separate (but identical) off-hook detectors and separate input lines to the microcontroller. The term, switch detector, would then be more appropriate than, off-hook detector. The second button could be dedicated to one function such as, voice command, leaving the other button free for the remaining functions. Rather than two buttons, a single button having three positions could be used with the two-wire scheme wherein one of the three switch positions would be detected by the second switch detector. Using the second wire for push button switch detection has a drawback, however: the wire is no longer free for the headset detect function. It would be desirable to find a solution to this dilemma.